Researchers at Johns Hopkins have identified a gene that, when repressed in tumor cells, puts a halt to cell growth and a range of processes needed for tumors to enlarge and spread to distant sites. The researchers hope that this so-called "master regulator" gene may be the key to developing a new treatment for tumors resistant to current drugs. "This master regulator is normally turned off in adult cells, but it is very active during embryonic development and in all highly aggressive tumors studied to date," says Linda Resar, M.D., an associate professor of medicine, oncology and pediatrics, and affiliate in the Institute for Cell Engineering at the Johns Hopkins University School of Medicine. "Our work shows for the first time that switching this gene off in aggressive cancer cells dramatically changes their appearance and behavior." A description of the experiments appears in the May 2 issue of the journal PLOS ONE.